Contact pieces



March 21, 1961 P. KOBLER 2,976,383

CONTACT PIECES Filed May 15, 1956 INVENTOR United States Patentofiifi 2., j

My invention relates particularly to the contact pieces in an electric shaver, with a motor of the contact breaker I type. It is known that with an electric shaver not only stubble of normal size, but also stubble of minute sizes is shaved olf. This extremely tiny stubble finds its way into the casing of the electric shaver and sooner or later finds its way to the contact pieces. Thereby it may happen, that one or more such hairs locate themselves between the two contact pieces. Through the heat of the electricity such stubble may emit a certain oily substance which then covers the surface of the contact pieces wherebythe electricityceases-toflow from one contact piece to the other, causing the motorto stop. This requires a cleaning repair job and it is the object of this invention to avoid such anoccurrence. j i i Another object of the invention is to have the contact pieces mounted on a base member, whereby it is possible to bring diiferent sections of the contact pieces into contact with each other.

Another object of the invention is to reduce the sparking area of the contact pieces to -a minimum and at the same time create a receding space or an open space on the sides of the contact spark area or surrounding that area, whereby stubble, falling between such contact pieces, will either be burned up in the restricted, but strongly intensified, sparking area, or will fall through the open space.

Another object of the invention is to cool the contact pieces with air. The invention consists of the facts that besides the special grinding of the contact pieces, at least one of these contact pieces is disposed at an angle, with respect to the other contact piece. As at least one of the contact pieces moves very rapidly back and forth, an air cooling of the contact pieces takes place. This cooling of the contact pieces is increased by the fact that the electric sparks are no more all over the contact piece, but are concentrated to a very small area. The heat of this restricted area flows over to the much larger surface of the contact piece without sparks. The larger area without sparks absorbs the heat and besides, the heat is cooled off by the air circulation which is created between the contact pieces. It is now possible to have the contact pieces on one end, far apart, whereby the air circulation is increased and with it the cooling off process. This increases the durability and efliciency of the contact pieces. This invention is therefore also for other applications, as for instance in the current distributor unit of automobiles, relays etc.

In the accompanying drawing the feature of the invention is shown with various embodiments thereof:

Fig. 1 is a side view of one contact piece.

Fig. 2 is another side view of a contact piece ground to a different shape.

Fig. 3 is also a side view of a contact piece, also ground dilferently.

Fig. 4 is a top view of Figs. 1, 2 or 3.

Fig. 5 is another side view of two contact pieces touching each other in a vertically inclined position.

Referringnow to the drawing: Fig. 1 shows the general outline of a contact piece 1. This contact piece l is usually supported by a spring or, as in this case, by lever means 2. By contact points, in electric shavers of the It will be noted that in Fig. 1 only one part or one section of the contact surface is ground off, shown with straight lines 3. Contact piece 1 is supported by a base member 4, which in turn is movably supported by supporting means 2. Base member 4 has flat side surfaces which make it possible to turn this base member into a different position with a wrench. A screw 5 attaches base member 4 to its supporting member 2. The screw 5 is held in position by a lockwasher 6. screw, a rivet 7, as shown in Fig. 5, may hold base mem her 4 in place, in such a way that this member 4 can still be turned into a different position if so desired. The

. contact piece 1 is usually hard soldered to the base memher 4, which is preferably made out of a different material.

It is understood that the contact piece 1 may also have flat side surfaces like base member 4, whereby base member 4 could be eliminated.

In Fig. 2 we see a contact piece with a ground-off part. 8. Comparing this ground-01f part 8 with the ground-off part 3 in Fig. l we see, that the ground-off surface is rounded off. 9 is the highestpoint on one side of this ground-01f part and 10 is the highest point on the other side of the ground-off part.

Fig. 3 shows another embodiment of a ground-off con i tact piece. The ground-off part creates a dividing line. between the ground-off part 11 and the other surface g Arrows 13 and 14 show the approximate sparking area where the electricity flows (12) of the contact piece.

from one contact piece to the other. It will be noticed that this dividing line between the two contact-piece surfaces runs approximately through the middle of the sparking area. On both sides of the sparking area the contact piece is ground oif, abruptly or gradually. The

purpose of this is to keep any hair stubble from locating r on or near the sparking area by encouraging it to fall away from the contact pieces. This is also illustrated in Fig. 5 where a ground-off part of the contact piece 1 creates an opening. The center of the sparking area 18 in Fig. 5 is away from the outside rim of the cont-act piece and forms above and below the sparking area an opening through which the stubble may fall.

Through creating a small sparking area, the heat intensity of the sparks is greatly increased, whereby stubble in its oily consistency will burn'up their oily consistency. Furthermore, the increased intensity of the sparks, in the small sparking area, causes an increased speed in the motor with a better shaving effect. The reduced surface of the sparking area reduces the amperes of the electricity going through the shaver, whereby much less overheating of the motor is achieved. By turning the contact pieces into different positions, relative to each other, the contact area may be in different inclinations towards each other or varied in the sparking area size, whereby the following combinations are possible:

(1) Less surface of sparking area, less amperes.

(2) More surface of the sparking area, less speed of themotor. I

(3) Less speed of the motor, less noise of the motor. (4) Less surface of the sparking area, greater speed of the motor. That is intensified sparks on a small area,

the sparking area on each contact piece over or near a bordering line between two slightly inclined contact surfaces.

Instead of a The best result is achieved by having the middle of the sparking area on both contact pieces on the dividing line of each contact piece, that is the dividing line between the inclined surfaces of each contact piece. Theoretically, on each contact piece there would be only one tiny spot which would indicate the center of the sparking area. This center would be preferably on the dividing line of two or more surfaces on each contact piece within the sparking area. This center being preferably the highest point in the sparking area, the surrounding area would gradually or abruptly fall off, that is slanting gradually or abruptly downward, away from the highest point of the sparking area. If there is a tiny flat surface in the center of the sparking area of each, or at least one, of the contact pieces, the efficiency can still be increased.

When the contact-sparking areas are ground off, the distance of the sparks moving from one contact piece to the other is slightly greater.

Usually the contact pieces in electric shavers are mounted on soft material. This makes it possible to bend the soft metal with a pair of pliers and to adjust the position of the surfaces of each contact point.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A contact structure comprising a pair of movable contact pieces, each contact piece having a concentrated sparking area spaced inwardly of the edges of the contact but outwardly of the center thereof, said sparking area being formed by a ground-off rim on at least a portion of the edge of the contact piece, each of said contact pieces comprising a large surface approximately as vw'de, as long, one of said contact pieces being arranged at an angle with respect to the other contact piece, said contact pieces touching each other at their concentrated sparking area" when in closed position, thereby forming a pair of V-shaped air pockets, one considerably larger than the other, the remaining noncontacting surfaces of the contact pieces forming heat radiating surfaces which are air cooled by the motion of at least one contact piece, said concentrated sparking area further being surrounded on at least two more sides by smaller air. pockets formed by the contact surfaces receding outwardly from the concentrated sparking area, and means for moving one contact piece with respect to the other for opening and closing a circuit.

2. A contact structure in accordance with claim 1 wherein at least one of said contact pieces is circular.

References Cited in the tile of this patent UNITED STATES PATENTS 675,293 Pieper May 28, 1901 1,653,823 Pudelko Dec. 27, 1927 1,786,797 Von Hoorn Dec. 30, 1930 1,971,506 Schick Aug. 28, 1934 2,212,858 Eickenmeyer Aug. 27, 1940 2,339,996 Kight Jan. 25, 1944 2,581,181 Favre Jan. 1, 1952 2,627,559- Netzel Feb. 3, 1953 2,696,665 Angst et al. Dec. 14, 1954 2,717,940 Fjellstedt Sept. 13, 1955 2,722,584 Skay Nov. 1, 1955 FOREIGN PATENTS 1,040,358 France May 20, 1953 

